This invention relates to structural stringers or beams adapted to form the structural frame of truck, bus or motorhome bodies and the like. More particularly, it is directed to a unique design extruded beam whereby two or more beams can be easily assembled to form a strong framework.
Metal frames for truck, bus or motorhome bodies are in common use. Most frequently such frames are built up from angles, box beams or other stringers fastened together in a variety of ways, such as rivets, bolts and/or welding. Although such structures are usually sound, assembly is difficult, an inventory of several different parts comprising the assembly is usually required, and several techniques such as cutting, drilling and/or welding are often required to complete the job. These problems are compounded by the fact that the available beams are not close tolerance members hence much time is wasted in cutting, fitting and adjusting.
Some close tolerance extruded members have been made available for special purposes such as assembling frames for windows, porches or furniture. A typical assembly of this type is disclosed in U.S. Pat. No. 3,848,387 wherein two separate extrusions of different designs are provided. One extrusion has a pair of longitudinal flanges of depth and spacing to fit into a complemental pair of flanges of different spacing and depth on the other extrusion.
The prior arrangement is useful for joining beams together in parallel longitudinal relationship or in angular relationship at their ends to form corners. However, they do not permit assembly of similar members transverse to each other intermediate the ends thus they have limited versatility. Also, since the disclosed extrusions cannot be identical, an inventory of both types is required.